Global warming is a popular term used to describe the increase in average global temperatures due to the greenhouse effect. Global warming has occurred in the distant past as the result of natural influences, but the term is most often used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gases. Global warming is thought to cause severe increases in Earth's atmospheric and surface temperatures, with disastrous environmental consequences such as changes in weather, sea levels, and land use patterns, commonly referred to as “climate change.” Global warming” is claimed to be so dangerous that it makes necessary a dramatic reduction in the burning of fossil fuels and a massive program to restructure our energy supply system.
Levels of several important greenhouse gases have increased by about 35 percent or more since large-scale industrialization began around 150 years ago. Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occuring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. In addition, very powerful greenhouse gases that are not naturally occurring include chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), which are generated in a variety of industrial processes. Other trace gases include carbon monoxide, hydrogen, HCFC-22, HCFC-141b, methyl halides, methyl chloroform, dichloromethane, chloroform, tetrachloroethylene, halons, bromoform, carbonyl sulfide, ethane, ethene, propane, propene, (i,n)-butane, butanes, acetylene, (i,n)-pentane or the like. Carbon dioxide, emitted by the combustion of fossil fuels such as coal, oil and gasoline, is the most abundant greenhouse gas after water vapor. As used herein, “greenhouse gases” are synonymous with “trace gases”, except water vapor which is not considered further because its concentration is fully determined by the climate system itself, not by human action directly.
Climate change induced by increasing mole fractions of various atmospheric constituents is a matter of immense importance. There is uncertainty in how the climate system varies naturally and reacts to emissions of greenhouse gases. Making progress in reducing uncertainties in projections of future climate requires better awareness and understanding of the buildup of greenhouse gases in the atmosphere and the behavior of the climate system. For effective management, a solid scientific understanding of their natural cycles and the processes that influence those cycles is necessary. To slow the rate of anthropogenic-induced climate change in the 21st century and to minimize its eventual magnitude, societies will need to manage the climate forcing factors that are directly influenced by human activities, in particular greenhouse gas and aerosol emissions. Precise and accurate atmospheric measurements are the touchstone of theories or models describing these cycles. Measurement data may be used to identify long-term trends, seasonal variability, and spatial distribution of greenhouse gases. Vertical profiles are an extremely important part of atmospheric science and gauge the gases' vertical journey as they rise from the Earth's surface into the upper atmosphere or vice versa. These “vertical profiles” can be used to test biogeochemical models of CO2, CH4, N20 and other gases that drive climate change. Vertical measurements show where the trace gas is in the atmosphere (i.e. at what height or altitude) and the quantity of trace gas in the atmosphere (its mole fraction, expressed as parts per million or parts per billion).
In addition, accurate and long-term records of atmospheric gases help advance global and regional environmental information and services regarding ozone depletion and baseline air quality.
The conventional approach to acquiring atmospheric samples for laboratory analysis is to use flask sampling. This is done by taking flask samples at different points in the atmosphere and bringing these flasks to a laboratory for precise mole fraction measurement of gaseous constituents. While good for point sampling, flask sampling requires multiple flasks and complicated sampling to acquire profile data. The complicated sampling requires opening each individual flask at the desired location in the atmosphere, collecting the sample, and closing each individual flask while moving through the atmosphere. Also, each of the flasks must be analyzed individually which increases the cost. For each doubling of the resolution requirement, i.e. resolution value halved, the number of flasks doubles and the number of analysis steps for the laboratory analysis also doubles. This greatly increases the cost of high resolution gas mole fraction profile measurements.
There are other ways of directly measuring atmospheric constituents. For example, laboratory equipment may be taken into the field on a stationary platform and measurements taken at a single point. There are generally two known techniques that may be used to measure the mole fraction of greenhouse gases: absorption of infrared light or by gas chromatography potentially followed by mass spectroscopy. Alternatively, measurement equipment may be placed on a mobile platform and measurements taken as the platform moves through the atmosphere. Unfortunately, the results obtained from these non-laboratory field condition tests are imprecise and inaccurate, difficult to obtain, and generally do not provide sufficient vertical resolution.
Accordingly, there has been a need for a system and method that reduce the costs associated with and simplify the acquisition of in-situ high resolution gas mole fraction profile measurements. There is also a need for a system and method that provide precise and accurate measurements, with improved resolution. There is also a need for a system and method which do not become appreciably more expensive as the vertical resolution increases. There is also a need for a system and method that do not require complicated configuration changes and sampling techniques. The present invention fulfills these needs and provides other related advantages.